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These guidelines provide thorough and consistent procedures for selecting and accommodating inflow design floods (IDFs), the flood flow above which the incremental increase in water surface elevation downstream due to the failure of a dam or other water retaining structure no longer presents an unacceptable additional downstream threat. These guidelines are not intended to provide a complete manual of all procedures for estimating IDFs; the selection of procedures is dependent upon available hydrologic data and individual watershed characteristics.

The main objectives of this document are to recommend appropriate procedures for selecting and accommodating the Inflow Design Flood for dams based on current and accepted practices and to promote a reasonable degree of consistency and uniformity among state and federal agencies.